For me the initial instructions about the ‘R’ was enough. I also think those kinds of mchanics tend to help keep players in the flow channel, as it tricks the player into feeling good about themself by teaching the game mechanics. A middle path might be to include a standard F1 for help, which lists all possible commands (but I don’t really think it is necessary).
About exhausting the options on an item, I had a chuckle at one of the feedbacks I got when I tried the game, which was something like “it’s not there anymore” (sorry, too lazy to try again). I think those kinds of responses work great for players with repeated actions, (e.g. “yet again, you look inside the chest hoping to find a pirate treasure. Again, there’s NOTHING IN THERE!” etc). It’s a little bit different when it comes to items that can be pickd up, but these should be rather easy to give a state (bool Removed false/true) and list as part of the text based on the bool’s value, don’t you think?